1. Field of the Invention
The present invention relates to an image recording apparatus, and more particularly, to an ink supply structure employed when ink is supplied from ink cartridges to a recording section.
2. Description of the Related Art
Conventionally, when an ink cartridge is disposed on a recording head, an inkjet printer becomes bulky with respect to a heightwise direction. For this reason, a known inkjet printer includes an ink cartridge, such as a cartridge-type ink tank, that is separated from a recording head (JP-A-2003-300330(see FIGS. 1, 6)).
In this printer, the ink cartridge has an ink storage section, and an ink outlet hole formed in a bottom surface of the ink storage section. An ink supply needle which can be inserted into the ink outlet hole of the ink cartridge is provided on a bottom section of a top-face-opened holder (a cartridge placement section) of a printer main body. An ink tube, which is connected at one end thereof to the ink supply needle, is connected to a recording head on a carriage which can reciprocally travel in a main scanning direction.
However, the image recording apparatus disclosed in JP-A-2003-300330 is not equipped with a device for unremovably retaining the ink cartridge attached to the holder. Therefore, when the image recording apparatus is inclined or the like, the ink supply needle might come off the ink outlet hole of the ink cartridge, which in turn causes entry of outside air into the ink cartridge. Subsequently, at the time of supply of ink, air is fed into the recording head along with ink through the ink tube. As a result, there arises a problem of deterioration of a recorded image, such as inaccurate ejection of ink from the recording head during image recording operation.
As described in JP-A-2003-300330, a needle section (needle-like projection section) used for establishing communication with the atmosphere is provided upright on the bottom of the holder in substantially parallel to the ink supply needle.
When ink is sucked from the ink storage section of the hermetic ink cartridge, the ink storage section is brought to a negative pressure (i.e., a pressure equal to atmospheric pressure or less), thereby ink supply operation cannot be continued. For this reason, the ink storage section is opened to the atmosphere through the atmosphere open hole formed in the ink cartridge. In this case, the structure is configured such that, when the ink cartridge is generally attached to the holder, a sealing film affixed to a recess section, or the like, which is formed in the bottom surface of the ink cartridge for opening the ink cartridge to the atmosphere is first broken; and such that, before the ink outlet hole is connected to the ink supply needle, the liquid surface of ink stored in the ink storage section within the ink cartridge is subjected to the atmospheric pressure, to thus smoothly supply ink to the ink tube or the inside of the recording head.
To that end, the attitude of the inserted ink cartridge must be regulated or guided so that, when the ink cartridge is inserted into the holder, at least the bottom surface of the ink cartridge can be inserted in parallel to the bottom surface of the holder and at least the sealing film can come close to the needle section (needle-like projection section) to communicate with the atmosphere, to thus break the sealing film. Such means is not taken into consideration by the related art.